1. Field of the Invention
The present invention relates to a dipping and pouring apparatus of molten metal, such as molten aluminium.
2. Description of Related Art
A ladle 50 as shown in FIG. 13 has been used to dip and transfer molten metal into a mold.
When the ladle 50 is directly plunged into, for example, molten aluminium contained in a furnace to scoop the molten metal, oxide produced in an upper surface portion of the molten metal in the furnace can be contained in the molten aluminium ladled in and by the ladle 50.
Furthermore, when the ladle 50 is inclined to transfer the ladled molten metal therefrom into a molding cavity through an outlet port 51 of the ladle 50, as shown in FIG. 13, the pour (quantity) and direction of a flow of the molten metal depend on the inclination angle of the ladle 50. Namely, as can be seen in FIG. 13, the flows "a" and "c" are farthest from and closest to the outlet port 51, respectively, and the flow "b" is intermediate therebetween. The quantity of molten metal decreases from the flow "a" towards the flow "c", and the pouring points of the flows "a", "b" and "c" are different from each other.
To eliminate the drawbacks mentioned above, the applicant of the present application has proposed an improved container for molten metal, including a movable refractory container body which is provided on the bottom thereof with a connecting passage opening into the air, and a valve stem which is reciprocally moved in the connecting passage to selectively establish the fluid connection of the connecting passage to the air (e.g., Japanese Unexamined Patent Publication No. 3-258455).
In the improved container, as disclosed in JPP '455, a constant quantity of molten metal can be poured from the container at the same pouring point thereof in the same direction. Furthermore, the molten metal is discharged from the bottom of the container, and accordingly, no oxide produced in the upper surface portion of the molten metal is poured in the molding cavity together with the molten metal.
Nevertheless, in the container disclosed in JPP '455, there are plurality of flows of molten metal produced when the molten metal flows through a plurality of connecting grooves formed in the valve stem, thus resulting in an occurrence of turbulence.
Upon pouring, the molten metal may be scattered due to the turbulent flows, so that the molding dies or surroundings thereof can be soiled with the scattered molten metal, or air bubbles can be contained in the molten metal.
The primary object of the present invention is to eliminate the drawbacks mentioned above by providing a dipping and pouring apparatus in which a constant quantity of molten metal can be poured in the same direction at a constant pouring point, without occurring a turbulence flow.